newlocale(3) — Linux manual page


newlocale(3)            Library Functions Manual            newlocale(3)

NAME         top

       newlocale, freelocale - create, modify, and free a locale object

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #include <locale.h>

       locale_t newlocale(int category_mask, const char *locale,
                          locale_t base);
       void freelocale(locale_t locobj);

   Feature Test Macro Requirements for glibc (see

       newlocale(), freelocale():
           Since glibc 2.10:
               _XOPEN_SOURCE >= 700
           Before glibc 2.10:

DESCRIPTION         top

       The newlocale() function creates a new locale object, or modifies
       an existing object, returning a reference to the new or modified
       object as the function result.  Whether the call creates a new
       object or modifies an existing object is determined by the value
       of base:

       •  If base is (locale_t) 0, a new object is created.

       •  If base refers to valid existing locale object (i.e., an
          object returned by a previous call to newlocale() or
          duplocale(3)), then that object is modified by the call.  If
          the call is successful, the contents of base are unspecified
          (in particular, the object referred to by base may be freed,
          and a new object created).  Therefore, the caller should
          ensure that it stops using base before the call to
          newlocale(), and should subsequently refer to the modified
          object via the reference returned as the function result.  If
          the call fails, the contents of base remain valid and

       If base is the special locale object LC_GLOBAL_LOCALE (see
       duplocale(3)), or is not (locale_t) 0 and is not a valid locale
       object handle, the behavior is undefined.

       The category_mask argument is a bit mask that specifies the
       locale categories that are to be set in a newly created locale
       object or modified in an existing object.  The mask is
       constructed by a bitwise OR of the constants LC_ADDRESS_MASK,
       and LC_TIME_MASK.  Alternatively, the mask can be specified as
       LC_ALL_MASK, which is equivalent to ORing all of the preceding

       For each category specified in category_mask, the locale data
       from locale will be used in the object returned by newlocale().
       If a new locale object is being created, data for all categories
       not specified in category_mask is taken from the default
       ("POSIX") locale.

       The following preset values of locale are defined for all
       categories that can be specified in category_mask:

              A minimal locale environment for C language programs.

       "C"    Equivalent to "POSIX".

       ""     An implementation-defined native environment corresponding
              to the values of the LC_* and LANG environment variables
              (see locale(7)).

       The freelocale() function deallocates the resources associated
       with locobj, a locale object previously returned by a call to
       newlocale() or duplocale(3).  If locobj is LC_GLOBAL_LOCALE or is
       not valid locale object handle, the results are undefined.

       Once a locale object has been freed, the program should make no
       further use of it.

RETURN VALUE         top

       On success, newlocale() returns a handle that can be used in
       calls to duplocale(3), freelocale(), and other functions that
       take a locale_t argument.  On error, newlocale() returns
       (locale_t) 0, and sets errno to indicate the error.

ERRORS         top

       EINVAL One or more bits in category_mask do not correspond to a
              valid locale category.

       EINVAL locale is NULL.

       ENOENT locale is not a string pointer referring to a valid

       ENOMEM Insufficient memory to create a locale object.

STANDARDS         top


HISTORY         top

       glibc 2.3.

NOTES         top

       Each locale object created by newlocale() should be deallocated
       using freelocale().

EXAMPLES         top

       The program below takes up to two command-line arguments, which
       each identify locales.  The first argument is required, and is
       used to set the LC_NUMERIC category in a locale object created
       using newlocale().  The second command-line argument is optional;
       if it is present, it is used to set the LC_TIME category of the
       locale object.

       Having created and initialized the locale object, the program
       then applies it using uselocale(3), and then tests the effect of
       the locale changes by:

       (1)  Displaying a floating-point number with a fractional part.
            This output will be affected by the LC_NUMERIC setting.  In
            many European-language locales, the fractional part of the
            number is separated from the integer part using a comma,
            rather than a period.

       (2)  Displaying the date.  The format and language of the output
            will be affected by the LC_TIME setting.

       The following shell sessions show some example runs of this

       Set the LC_NUMERIC category to fr_FR (French):

           $ ./a.out fr_FR
           Fri Mar  7 00:25:08 2014

       Set the LC_NUMERIC category to fr_FR (French), and the LC_TIME
       category to it_IT (Italian):

           $ ./a.out fr_FR it_IT
           ven 07 mar 2014 00:26:01 CET

       Specify the LC_TIME setting as an empty string, which causes the
       value to be taken from environment variable settings (which,
       here, specify mi_NZ, New Zealand Māori):

           $ LC_ALL=mi_NZ ./a.out fr_FR ""
           Te Paraire, te 07 o Poutū-te-rangi, 2014 00:38:44 CET

   Program source
       #define _XOPEN_SOURCE 700
       #include <locale.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <time.h>

       #define errExit(msg)    do { perror(msg); exit(EXIT_FAILURE); \
                               } while (0)

       main(int argc, char *argv[])
           char buf[100];
           time_t t;
           size_t s;
           struct tm *tm;
           locale_t loc, nloc;

           if (argc < 2) {
               fprintf(stderr, "Usage: %s locale1 [locale2]\n", argv[0]);

           /* Create a new locale object, taking the LC_NUMERIC settings
              from the locale specified in argv[1]. */

           loc = newlocale(LC_NUMERIC_MASK, argv[1], (locale_t) 0);
           if (loc == (locale_t) 0)

           /* If a second command-line argument was specified, modify the
              locale object to take the LC_TIME settings from the locale
              specified in argv[2]. We assign the result of this newlocale()
              call to 'nloc' rather than 'loc', since in some cases, we might
              want to preserve 'loc' if this call fails. */

           if (argc > 2) {
               nloc = newlocale(LC_TIME_MASK, argv[2], loc);
               if (nloc == (locale_t) 0)
               loc = nloc;

           /* Apply the newly created locale to this thread. */


           /* Test effect of LC_NUMERIC. */

           printf("%8.3f\n", 123456.789);

           /* Test effect of LC_TIME. */

           t = time(NULL);
           tm = localtime(&t);
           if (tm == NULL)

           s = strftime(buf, sizeof(buf), "%c", tm);
           if (s == 0)

           printf("%s\n", buf);

           /* Free the locale object. */

           uselocale(LC_GLOBAL_LOCALE);    /* So 'loc' is no longer in use */


SEE ALSO         top

       locale(1), duplocale(3), setlocale(3), uselocale(3), locale(5),

Linux man-pages (unreleased)   2024-05-02                   newlocale(3)

Pages that refer to this page: duplocale(3)isalpha(3)locale_t(3type)nl_langinfo(3)toupper(3)uselocale(3)locale(5)locale(7)